松辽盆地西北边界部分地球物理特征

松辽盆地是我国东北地区重要的地质构造单元.为探测松辽盆地西北部边界基底分布、深部结构与构造关系,沿扎兰屯经齐齐哈尔至林甸实施了约240 km的综合地球物理的探测研究,利用重力、电法等地球物理方法对其进行了综合地球物理解释.研究结果揭示了研究区的速度结构分布、重力分布、基底起伏形态及电性结构等地球物理特征:(1)满-绥断面速度资料显示,嫩江岩石圈断裂有明显的速度分界,其东南侧的松辽盆地与大杨树坳陷具有连续统一的速度结构;(2)重力反演基底显示,松辽盆地与大杨树坳陷基底连续,具有统一的基底特征;(3)二维电性反演显示,大杨树坳陷和松辽盆地两构造电性层连在一起,低阻分布形态也是一样的.以上结果结合满-绥断面速度结构分布表明大杨树坳陷是松辽盆地西部的延续,松辽盆地西部边界应扩展到大杨树坳陷西部边界,即嫩江岩石圈断裂.

Partial geophysical features of the northwest boundary in Songliao basin

Songliao basin is an important geologic structural unit in the northeast part of China.its structure meaning has drawn extensive attention.To detect the relationship of deep crust construction and structure between Songliao massive and its southeast region,a research of general geophysical detection from Zhalantun, bypass Qiqihar,to Lindian(about 240 km) has been conducted and the general geophysical interpretation has been gotten by methods of velocity,gravity and electricity etc.the result has distinctly revealed the geophysical features such as gravity distributing,foundation form and electrical structure etc.(1) The gravity anomaly of Longjiang ridge belt(the southeast extand of Dayangshu basin) are exactly corresponding to the high resistivity in electrical data.(2)The gravity inversion data show that the basement of Songliao basin is continuous with the Dayangshu Depression's and they have uniform features of the basement.(3)2-D electrical inversion data show that the deep electrical layers of Dayangshu Depression and Songliao basin are hang together and the distributions of them are coherent too.In conclusion,the Dayangshu Depression is the extend of the west Songliao basin.The west edge of Songliao basin should be west boundary of Dayangshu Depression,that is the Nenjiang geosphere rupture.